F12 · Flying Insect
Drain Fly
Clogmia albipunctata
Small fuzzy moth-like flies that breed in the slimy gunk inside drains. A sign of organic build-up.
- Size
- 2–5 mm
- Habitat
- Drains, overflows, sewage pipes, damp grout
- Activity
- Year-round indoors, warm months outdoors
Overview
Also known as moth flies or sewer flies. Adults are weak fliers and tend to rest on walls near sinks, showers and floor wastes. They breed in the gelatinous biofilm that lines drain pipes — sprays kill adults but the larvae keep hatching until the biofilm is physically removed. Fix the breeding site and the problem is gone in a week.
How to identify
- Tiny (2–5 mm), fuzzy body with broad rounded wings held roof-like over the body
- Grey to tan with a moth-like appearance
- Found resting on bathroom or laundry walls near drains
- Test: tape a clear cup over the suspect drain overnight — trapped adults confirm the source
Pro Tip
Sprays kill the adults you see; the larvae stay in the drain. Clean the pipe and they're gone.
General guidance only. Information on Home Pest Defence is provided for educational purposes and is not a substitute for professional advice. For termites, venomous spider bites, wasp nests in walls, or protected wildlife, contact a licensed pest controller, your GP, or the relevant state wildlife authority. In emergencies call 000; for poisoning call 13 11 26.